1. Field of the Invention
The present invention relates to a novel sustained release pharmaceutical tablet, and more particularly, a sustained release magnesium lactate pharmaceutical tablet.
2. Description of Prior Art
Within the past few years, increased attention has been placed on the maintenance of a sufficient amount of magnesium in the human body. The maintenance of proper amounts of magnesium can help prevent myocardial ischemia and infarction, electrolyte deficiency resulting from malnutrition or diuretics and complications of treatment with digitalis glycosides and type 1 or 3 antiarrhythmic drugs. Cardiovascular News, Oct. 1986, Vol. 50, No. 10, Page 5.
Recent studies have suggested that supplementing the diet with magnesium may be effective in reducing the likelihood of arrhythmia Cardiovascular News, Oct. 1986, Vol. 50, No. 10, Page 5; Modern Medicine, July 1986, Vol. 54, No. 7, Pages 136-138; Modern Medicine, April 1983, Vol. 51, No. 4, Page 153; The Lancet, Vol. 2, No. 8566, Oct. 31, 1987, Page 1019; Circulation, Vol. 77, No. 2, Pages 392-397, February 1985; and Medical World News, Vol. 27, No. 7, Apr. 14, 1986, Pages 40-41.
Means for providing magnesium to the human body as a supplement have been proposed in the art For example, for the treatment of arrhythmia, magnesium sulfate has been intravenously administered to patients. Other dietary supplements have included magnesium oxide, magnesium hydroxide and magnesium carbonate. Despite the ability of these compounds to increase magnesium levels, they are primarily insoluble in the gastro-intestinal tract, and hence, not easily delivered to the gastro-intestinal system.
G. D. Searle and Co. has commercially marketed the "Slow-Mag" magnesium chloride delayed release composition as a magnesium supplement. The active magnesium chloride material is highly soluble, and is capable of being released over a gradual period of time. In practice, the magnesium chloride tablet is coated with an enteric coating to enable the magnesium chloride to be released and absorbed in the small intestine, and not in the stomach.
Standard Process Labs, Inc., of Palmyra, Wisconsin has sold gelatin capsules containing magnesium lactate powder. Each capsule contains approximately 70 milligrams of magnesium lactate. The amount of magnesium maintained within the capsules is relatively small, totaling to less than one milliequivalent. Accordingly, to administer a large dose of magnesium for therapeutic treatment, for example 7 milliequivalents, approximately 12 capsules have to be consumed on a daily basis. Needless to say, the high quantity of capsules which have to be swallowed per day can be burdensome. Moreover, once the capsule walls have been dissolved by the gastro-intestinal system, the entire contents of the capsule are immediately distributed to the gastro-intestinal system, and are not gradually released over a period of time. If too much magnesium lactate is delivered to one portion of the gastro-intestinal tract at one time, side effects, for example diarrhea, lesions and chemical imbalance may result.
Because of the high solubility of magnesium lactate in the gastro-intestinal system, it would be particularly desirable to develop a product which is capable of gradually releasing magnesium lactate to the gastro-intestinal system over an extended period of time, for example 7 to 12 hours. The ideal form for such a composition is a gradual-release tablet. Gradual-release tablets are known in the art. Examples of such tablets are set forth in U.S. Pat. No. 3,456,049, assigned to Ciba Corporation. To date, magnesium lactate has not been manufactured in tablet form. It is hypothesized that magnesium lactate has not been produced in tablet form because it is a highly non-compressible powder material. As such, it is extremely difficult to compress the material into tablet form.
Accordingly, there exists a need in the art for a gradual release pharmaceutical composition, and particularly a gradual release magnesium lactate tablet which supplies magnesium to the gastro-intestinal tract over an extended period of time with reduced risk of side effects.